1. Field of the Invention
This invention relates in general to navigation systems, and more particularly to a navigation system incorporating artificial intelligence that is useful for cars and trucks requiring no sensors for spatially locating the vehicle and which uses an audio, rather than visual, interface with the driver.
2. Description of the Related Art
Many existing navigation systems utilize internal sensors or navigation satellites to locate the subject vehicle with respect to a digital map and then, once located, create a visual presentation of the map, the location of the vehicle and the destination point on a CRT mounted in the dashboard or elsewhere in the vehicle. Some systems also calculate a preferred route which is highlighted on the displayed map. A great deal of effort and technology is used in these systems in order to locate the vehicle as accurately as possible in order to perform the navigation function.
U.S. Pat. Nos. 4,630,209; 4,829,578; 4,502,123; 4,242,731; 4,679,147; 4,796,189; 4,677,429; 4,882,696; 4,749,924; 4,758,959 and 4,827,520 pertain to car navigation systems or to voice actuated control of a vehicle and are representative of these existing navigation systems.
For example, U.S. Pat. No. 4,758,959 issued to Thoone et al., is indicative of both the ability and shortcomings of the existing systems. In U.S. Pat. No. 4,758,959, speedometers and accelerometers are utilized to estimate the vehicle's position and corrections are made to try to keep the vehicle positioned on the map. The map and the vehicle are displayed on a CRT. The operator inputs his source and destination points via a keyboard.
The problems associated with this kind of system are as follows:
1. The accelerometer and velocity sensors are subject to drift and can go out of calibration. Even if the sensors were perfect or if very accurate satellite positioning were possible, the maps available are not accurate, having been digitized from maps which are essentially hand drawn. Thus, it is difficult to determine what street or section of street the vehicle is actually on.
2. The presentation of a map on a CRT in a moving vehicle is a dangerous distraction, especially in heavy traffic found around cities.
3. The use of a keyboard for input from the driver is another distraction and could be dangerous to use while the vehicle is in motion.
4. The use of on-board sensors requires the use of specialized procedures with specially trained personnel for proper installation. Typically, this kind of installation is best done at the factory where the vehicle is built. Therefore, these devices miss the broad after-market of existing cars.